Significant combustion research is being directed at developing small scale combustion systems capable of generating power in the 1 W to 1000 W range. These small scale power systems are envisioned to replace the conventional chemical batteries for portable electronics, where the power source forms a large fraction of the total system weight. The high energy density of fuels and the prospect of converting fuel's chemical energy into power have drawn researchers to the field of micro-electro-mechanical or MEMS engines. However, for practical reasons, recent research has focused on meso-scale systems with the length scale ranging from few mm to few cm. Meso-scale heat engines could provide high efficiency and longevity, unattainable with MEMS devices. Combustion at small scales is also a topic of significant fundamental research because of the challenges it presents in terms of fuel-air mixing and combustion efficiency.